This invention concerns a machine for separating a heterogenous flow of recyclable matter into respective separate streams of recyclable materal, with each stream including a respective homogenous class or classes of articles.
Machines are known which receive a heterogenous flow of recyclable matter and separate the flow into respective streams which include one or more homogenous classes of material. Presently, most of these machines separate the input flow into at least three separate material streams. The first stream includes magneto-responsive articles such as tin cans and ferrous scrap. The second stream consists of relatively light materials such as aluminum cans, plastic containers, and paper objects. The third stream includes relatively heavy articles such as glass containers, which are not responsive to a magnetizing force.
The known machines employ magnetic means to extract magneto-responsive materials. The resulting stream of recyclable matter is separated into the second and third streams by applying a high-velocity air flow, either in the form of a vacuum or a high-pressure air stream, to blow the lighter articles away from the heavier articles. The three streams are directed by these prior art machines to respective conveyor mechanisms for transport to sorting stations where human operators further classify and sort the streams.
Separator machines which are known in the art exhibit several significant disadvantages. First, most provide a stream of input matter which has been densified by collection, transport, and storage. The input stream is typically input to a separator machine on a conveyor, without having been loosened. This makes it more difficult to process the stream for separation and tends to retain small waste particles in the constituent materials, even after separation.
The relatively dense input flow leads to a second significant disadvantage of known separator machines. Such machines typically extract magneto-responsive articles relatively early in the separation process. Indeed, two such machines remove magneto-responsive articles at the top end of an inclined conveyor which carries the input stream. Early removal from a relatively dense stream frequently results in other articles being pulled out of the input stream with the magneto-responsive articles. Moreover, a dense and deep input stream can block or dislodge magneto-responsive articles from a magnetic extractor. Further, the mechanisms for extracting the magneto-responsive articles are large, expensive, and difficult to maintain.
A third significant disadvantage of known separator machines is the high breakage rate of glass containers. The glass containers normally are divided from other containers in an air separator which allows the glass containers to drop vertically. In such machines, glass containers are allowed to free-fall through the air separator mechanism to a conveyor. The conveyors move the glass containers at a relatively low speed, which results in falling glass containers impacting on other containers which are being transported by the conveyor. The result is a high frequency of glass-glass collisions and a very high rate of glass breakage. This is undesirable because of the potential of harm to human operators, because of the difficulty of extracting the broken material, and because of the creation of a significant amount of non-recoverable waste in the form of small glass particles.